Telephone-exchange system



S. B. WILLIAMS, JR. TELEPHONE EXCHANGE sYsTEIvI.

APPLICATION FILED IIIAYI6,`I9I9.

Patented June 14, 1921.

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S. B. WILLIAMS, Jn. TELEPHONE EXCHANGE SYSTEM. APPLICATION FILED MAY16. 1919.

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T'- APPLICATION FILED MAY I6. 1919. 1,381,530.

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S. B. WILLIAMS, In.

TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED MAYIG. I9I9.

1,381 ,530. Patented June 14,1921.

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1S. B. WILLIAMS, JR.

4TELEPHONE EXCHANGE SYSTEM.

- APPLICATION man MAY 16, 1919.

1,381,530. PatentedJune 14, 192.1e

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APPLICATION man MAY 16, 1919. i 1,881,530, PmndJune 14, 1921.

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www \1 @L @i IIIIH H5 jl N s s S -9 A I h L a "v w N v h :q R w y Affy SAMUEL B. WILLIAMS, JR., OF BROOKLYN, NEW YORK,

TRIC COMPANY, INCORPORA'lliD,V OF NEW YORK, N.

YORK.

ASSIGNOR TO WESTERN ELEC- Y., A CORPORATION 0F NEW TELEPHONE-EXCHANGE SYSTEM.

Application inea May 1e,

To all whom t may concern Be it known that I, SAMUEL B. WILLIAMS, Jr., a citizen of the United States, residing at Brooklyn, in the county of Kings and State of New York, have invented certain new and useful Improvements in Telephone- Exchange Systems, of which the following is a full, clear, concise, and exact description.

This invention relates to controlling and signaling apparatus for telephone exchange systems, and more particularly to systems of the type employing automatic switches for extending connections to operators position connecting circuits through the niedium of which the connections are extended to called stations.

The invention has for its particular 0bject the provision of means for automatically informing an operator of the origin of connections that are extended to her position for completion, to enable the operator to follow. whatever prescribed routine of operation in handling the connection the origin of the call requires,-as in the han dling of calls from lines adapted for different classes of service, where the operator is required to perform certain special acts in taking care of calls from lines having certain classes of service.

Another object ofthe invention'is to provide for extending to the operators position all calls having` a common class of service or a similar origin by means of groups of trunks distinct from those that are employed in extending calls having another class of service or a different origin, and to provide the operator with ineansrfor auto'- matically indicating the particular group of trunks over which the call is extended, and hence the class of service or origin of that particular call. r

Another object is to provide indicating mechanism at the operators position automatically and selectively responsive to distinctive controlling means associated with the trunks of the various groups, so that a characteristic indication is automatically produced for each group of trunks over which connections are extended to the operators position. l

Anot'rier object of the invention is to prt Specification of Letters Patent.

Patented June 14, 1921.

1919. Serial N0. 297,448. Y

vide each connecting tors position with that automatically circuit of an operaregistering mechanism n l receives a different setting in accordance with the trunk group over which a call is extended to that connecting circuit, and to provide a signal device common to all of the connecting circuits of the position, and adapted to be brought into temporary association )with any one. of them, for giving a characteristic signal indication in accordance with the setting of the register with rwhich the device is temporarily associated.

Another object of the invention is to provide for the control of the signal devices' at the operators position by means of synchronously operated switches, one of which is associated with the trunk circuit and successively connects with the circuit a series of controlling paths, and the other of which is associated with the connecting circuit to which the trunk circuit is extended and successively connects with that circuit a corresponding series of responsive devices, so that the responsive devices are successively brought under the control of their corre-` sponding controlling paths, and by their operated or non-operated conditions invarious combinations, in accordance with the condition of the corresponding controlling paths, bring abouttlie selective 'operation of the indicating devices.

A preferred embodiment of the system of the invention wherein the above-mentioned and other objects are realized, is illustrated .in theaccompanying drawings, in which igure 1 is a skeletonized diagrammatic illustration of a call distributing system organized for a class-of-service identiiication of the lines, and in which Figs..2 to 6, inclusive, taken together and arranged side by side in the manner indicated by ther circuit lines extending to the margins of the drawings, illustrate as much of the complete organization of a call distributing system embodying the features of the invention as is necessary to convey an understanding of its construction and mode of operation. i

In the skeleton form illustrated in Fig. 1, a number of groups of telephone lines are indicated, with means for extending the lines of each group to connecting circuits at different operators positions, the operators positions being provided with means tor informing the operator of the class of service of the calling line, and for enabling lier to connect the calling line with the desired called line. In the present instance the telephone lines are shown to be segregated in accordance with their class of service into six groups, group A containing the flat rate individual and PBX lines, group B containing the fiat rate party lines, group C containing the message rate individual lines, group D containing the message rate party lines, group E containing the message rate PBX lines, and group F containing the pay station lines. Associated with each of these groups of lines is a group of finder circircuits F, F', the finder circuits terminating at one end in line finder switches LF and LF (Fig. 2), and at the other end in cord selectors CS and CS V(Fig. 3). The line finder switches are automatically actuated to'malre connection with any calling line of the group of lines-that they serve, and the cord selector switches are automatically actuated tol extend the finder circuit that has seized a calling line to a( connecting circuit CC terminating in a connecting plug at one of the operators positions P, P P2.

At each operators position is a class-ofservice signal device L which is adapted to be brought into operative relation with any of the class-of-service registering mechanisms W, of which there is one for each of the connecting circuits CC of the corresponding position. Each of the class-o-service registering mechanisms W includes a number of relays R, R', R2, the operative relation ofl which with the associated connecting circuit GC is controlled by a switch .400. Each of the finder circuits F, F', is provided with a switch 300 which coperates with the switch L100 of the connecting circuit in the-control of the class-of-service registering mechanism W of the connecting circuitto which the nder circuit is extended.

When any of the lines of any of the groups, A,B, C, D,y E, F, calls, it is automatically extended, by means of one of thel iinder circuits of the associated group of finder circuits, to an idle connecting circuit CC of one otv the operators positions P which happens atthe time to-be available. In extending the call the switches 300 of the iinder circuit and 400 of thev connecting circuit operate to bring their respective circuits synchronously into operative relation with a series or associated contact points, the switch 400 through its contact points bringing the series of relays R, R and R2 successively intooperative relation with the connectingV circuit over which the call has been extended. and the switch 300 of the corresponding finder circuit through its contact points operating to establish or fail to establish energizing paths for the relays R, R or R2 which are at the same instant connected to the connecting circuit by the switch 400. Consequently, which of the relaysof the class-.ofservice registering mechanism W are operated depends upon the connections .that are provided or omitted from the contact points of vthe switch 300 of the finder circuit that hasextended the calling line. The consequent operated or non-operated condition ot the relays R, R, R2 creates a ccndition or setting of the registering device W which differs in accordance with whetherthe call has been extended by way of one or another ot the groups ot finder or trunk circuits, and to which the condition or setting of the class-o-service signal device L isselectively responsive when it is brought into operative relation with the registering mechanism.

The class-o-service signal device L includes, in the present instance, six lamps, AL, BL, CL, DL, EL, and FL. The illumination of these lamps is under the control of the relays R, R and R2 of the indicator, the relation. between the energizing. circuits of the lamps and the circuits of the registering mechanism being such that a diierent lampis lighted for each ofthe six diiierent groups from which a call may be extended. rihe invention is capable or use in connectionrwith a wide variety or" systems and organizations; but for convenience it is preferred in the present case to show and decribe it as incorporated in a call distributing system of the type that is disclosed in the application of S. B. Williams, Jr., Serial No. 229,035 (Case 36), filed April 17, 1018. lnasmuch as the entire organization disclosed in the above mentioned applicatien is not required for an understanding of the application of the present invention to such a system, the parts which seem unnecessary to a full disclosure of the present invention have been omitted.

As illustrated in Figs. 2 to 6, inclusive, a single group of telephone lines is indicated, and two linesof the group are shown, one incompletely and the other as-extending to station C. The particular group which is chosen i'or the purpose of illustration isthe C group containing the message rate individual lines, each one olf-which is provided with a message register'QQ. Theilines or this group are served by line iinder switches LF, two of which are shown. It may be assumed that the other line groups into which the lines cf the telephone exchange are segregated may similarly be served by other line linder switches.

The group ci lines Chas access to groups or' connecting circuits CC through the medium ci a group of finder circuits F, it being` assumed that the one connecting circuit and one finder ircuit illustrated are repre- Vinto engagement sentative of the plurality of circuits of the respective groups. The finder circuits terminate upon the brushes of theV line finder switches LF and cord selector switches CS. The contact terminals of the line finder switches are connected to the subscribers lines, and the contact terminals of the cord selector switches are connected to the connecting `circuits of the various operators positions. The contactterminals of the cord selector switches are divided into groups, each adapted to be engagedv by a different set of brushes of the'cord selector; and each group' of contacts constitutes the terminals of a group of connecting circuits leading to a different operators position. As illustrated, the lines of group C have access to the connecting circuits of the different op'- erators positions through the medium 'of the cord selector switches that are illustrated, while the lines of other groups have access to the same connecting vcircuits through the medium of other cord selector switches to the terminals of which the conneet-ing circuits CC are multiplied.

Each of the connecting circuits terminates upon a calling plug-334 that is adapted to be inserted into spring jacks 339Tof the various lines that may becalled; and is also provided, in addition to the usual supervisory lamps, keys, and so forth, withregistering mechanism W which is adapted to receive a distinctive setting under the` control of switch contacts 305, one of which is associated with each'of the finder circuits that imay extend a connection to a connecting circuit. 'f

TheV` operators position apparatus, as illustrated in thel present instance, includes the usual operators telephone set and con'- trolling keys, and also a class-of-service signal device L comprising a group of lamps, AL, BL,v CL, DL, EL and FL that are adapted to be brought into operative relation with any-connecting circuit of the position with which the operators telephone set may at the time be connected. i The cordv selector switches CS may be substantially like the switch illustrated and .described in Patentf No. 1,177 ,044 to James L.y McQuarrie issued l-,March L28th, 1916.y

Each comprises a longitudinally Vmovable shaft 1,'.carryingV as many sets ofy brushes 2 as there are groups of stationary terminals to be engaged. To move the shaft'up, an extension at the lower end ofthe shaft is brought with the constantly rotaing power member 3 by means of an idler wheel operated by the up-drive magnet 34; and to move the shaft down, the extension is brought into engagement with the power member 4 by mea-ns of an'idler wheel operated by the down-driveimagnet 3.5. v Normally, the brushes of each fof the sets 2 are held apart so asta-clear the associated terminals bymeansl of a separating cam 5 1ocated between the innermost brushes of the set. The cam 5 is rotatably mounted, and when rotated in 'one direction, releases the brushes and permits them to engage the associated terminals. The tripping or releasing of the brushes is controlled by a number of trip magnets, as 21 -and`22, Each of these, when energized, rotates an associated trip rod 6 that extends transversely to the switch shafts 1 and carries as many trip 4yokes 7 as there are finder switches or selector switches in the group. The trip rod in vrotating brings all of its trip yokes 7 into position to operate the brush-controlling cams 5 of the corresponding sets of brushes on all of the switches, so that whichever of the finder switches isr caused to move up, has that set of brushes tripped that corresponds with the particular trip magnet 21, 22, that is -at the time energized. When the finder switch that has been in use is returned to its normal position, any of the associated controlling cams 5 that has been tripped, is engaged and rotated in a reverse direction to separate its switch springs againand thus render them inactive. Each of the cord selector switches has associated with it a commutator 8,.which comprises a number of stationary commutator segment-s and a set of movable brushes Vcarried at the top of the switch sha-ft 1 and coperating with the stationary segments. This commutator serves to make and break a number of controlling circuits in the yvarious stages of the upward movement ofthe switch shaft.

VThe line finder switches LF may be like the cord selector switches described above; but to simplify the disclosure of the system in which the present invention is embodied, the line finder switches have been shown as switches carrying only a single set of brushes and a single group of line contacts, this arrangement serving the operative requirements of the 'system as it is here disclosed.

For controlling the circuits of the organization there are employed a number of Sequence switches which are shown at different points and designated200, 300 and 400, respectively. These .sequence switches may be of the type disclosed in' Patent No. 1,127,808, issued February 9, 1915, to Reynolds and Baldwin. "Each consists of an electro-magnetically controlled motor or driving mechanism, a cam and a number of associated switch contacts. To each of the Contacts associatedwith the various sequence switch cams are applied certain numerals. These numerals in the case of the contacts 201, 301 and 401 indicate the only positions of the associated sequence switch in which these particular contacts are open; the numerals applied to all of the other sequence switch contacts indicatethe .only positions of the particular .sequence switchzin which these contacts are'closed.

' l Operation.

- for connection takes-his telephone receiver l therefore is not from its hook. Associated with each group of lines is a distributer switch .130 whose wipers 131, 132 'and 133 are connected with a cut-in relay 11 and a test relay 12, and whose contact banks are connected with the line and local conductors of the vario-us lines of the group. When the wipers of the distributer switch 130, which is continuously operated in any desired manner, are moved, into position where they are in engagement with the conductors .of the line extending to station7 C', a circuit is completed for the energi'zation of the cut-in relay 11 by way of conductor 53 and the' windings oit the message register 92; and the instant the cut-in relay operates ity closesa circuit that includes the windings ofthe test relay 12 serially in the circuit of the calling line, whose circuit at the vsubstation vhas been closed bythe taking ofthe telephone 'receiver from its hook. As a result relay 12 operates and applies a ground, which, through the medium of apparatus that forms no part of the present invention, and which illustrated and described, brings about the energization of the Vstarting relay 24. Relay 24 .in operating closes a circuit that extends from battery by `way of selector sequence switch Contact 320 (1to4), winding of relay 30, selector sequence switch contact 309 (1 to 11), finder lsequence switch contact 217 (2), conductor 29, and armature and front contact of relay 24 to ground. Of the group of finder circuits that -are adapted to serve the group of lines of `which this particular calling line is one, only one of the inder circuits has its sequence switch normally restingin position 2, the relation ship betweenthe finder circuits being such that whenever one of them responds to a calling line and hasits Vsequence switch 200 moved out4 of position 2, another ofthe finder circuits vhas its sequence switch 200 moved fromcposition 1 to position-2 in order to be in readiness to respond to the next calling line.

Upon the closure of the circuit `just traced, as a result of the operation of relay 24, relay 30 is operated and closes a locking circuit for itself that extends by way of the lefthand Jfront Contact and armature of :relay 30, selectorl sequence switch contact 317 (1) and finder sequence switch contact 216 (2 to 3) to ground. Relay 30 in operating also is` not closes a circuit that extends from battery through the motor magnet and conatctV 203 (2) of the finder sequence switch and righthand front contact and armature oi relay 30 to ground. As acresult, the finder sequence switch 200 moves out. of position 2 and comes to rest in .position 3.

At the instant relay 24 operates as a re` sult of the initiation of the call, a circuit is completed that extends from battery through theup-drive magnet Y32 of the line finder LF, conductor 59, finder sequence switch contact 213 (2 to 2%), finder sequence switch contact 217 (2), conductor 29, and armaturev and front contact of relay 24 to ground. This starts the upward movement of the brushes of the line finder switch. The movement of the finder sequence switch out of lposition 2 opens this energizing circuit for .up-drive magnet 32; but another branch to ground Jfor continuing the energization of the up-drive magnet has been completed to ground by'way of the left-hand front contact and armature' of relay V30, selector sequence switch contact 317 (1) and finder sequence switch contact 216 (2 to V3). This energizing path is opened at finder sequence switch contact'213 (2 to as the finder sequence switch moves from position 2 to position 3,.but at the same time is closed to ground bywayfo'f the back contact and right-hand armature of relay 37 at inder sequence switch Contact 213 (24ste 3).? Consequently the circuit of the up-drive magnet 32,'closed when the relay 24 operates, continues closed subject to the control of the right-hand back contact vand armature of relay 37. A

- As the brushes of the line flnderLF are moved up as al result oit the energization of the up-drive magnet 32, they successively engage contact terminals` associated with the various lines in the ,group in which the calling line C is located. As each set of ter1ninals is engaged, a circuit is completed for relay 52 by way of finder sequence switch contact 209 (2 to 3) conductor50, brush 42 andjcontact 46 of the finder switch, and conductor 53 of the line at that instant engaged.

1f the line is busy, either as a calling line or a: called line, relay 52 is shunted out and operated; lbut if the lite is'not elseY where connected with, relay 52 .Lis operated over the circuit'just described for it and in operating includes the windings of relay 37 serially in circuitwith the talking conductors of the line over which the line finder brushes are passing. 1f the line thus tested is not calling, 'its circuitV is open at the subscribers station; but it the line is calling, the removal of the receiver from its hook has closed the circuit at the substation, and therefore .relay -37 is energized. Consequently `relay 37 operates the instant the terminals of the calling line are engaged,

and in operating Vbreaks thepreviouslytraced energizing circuit of the Lip-drive magnet 32 at the right-hand back contact and armature of relay 37. This stops the brushes of the line finder in engagement with the terminals of the calling line, and extends the circuit of that line to the finder circuit. Relay 37 in operating also closes a locking circuit for itself by way of its left-hand winding, its lett-hand armature and front contact and finder sequence switch contact 219 (3), and at the saine time closes a circuit by way of its right-hand armature and front contact and linder sequence switch contact 206 (3) that operates the finder sequence switch and causes it to move out of position 3 and come to rest in position 4.

In moving out of position 3 the finder sequence switch disconnects the cut-in relay 52 and the test relay 37, and in position 4 applies battery to test conductor 53 of the calling line by way of resistance 54 and finder sequence switch contact 210 (4 to and conductor 50, this battery connection serving to guard the calling line against in terference while the finder sequence switch rests in position 4. In position 4 the finder sequence switch also closes a circuit which extends fromk battery through the motor magnet and contact 302 (1) of the selector sequence switch, contact 220 (4) of the finder' sequence switch and right-hand back contact and armature of relay 37 to ground.

After the selector sequence switch 300 reaches position 2. it is moved in any desired manner, such as by the control over it of portions of the organization that may be employed :tor determining the selection of a particular operators position; until it reaches position 6. Such additional parts of the organization are illustrated in the previously-mentioned application of S. B. Williams, Jr., and may be provided if desired, but are not here shown as they are not regarded as essential to an understanding of the particular invention herein disclosed.

When the selector sequence switch 300 reaches position 6, a circuit is closed that extends from battery through the winding of the up-drive magnet 34 of the cord selector CS, conductor 89, selector sequence switch contact 316 k(5 to 6) and right-hand back contact and armature of relay 30 to ground. This starts the upward movement of the cord selector brushes. In the meanwhile one of the magnets 21, 22 of the cord selector has been energized by closing its circuit in any convenient manner, the particular relay energized depending upon 'which of the operators positions to which the cord selector has access is available for receiving the call. Consequently when the upward movement of the cord ,selector brushes starts, one of the sets is tripped and made active to engage the contacts of the corresponding bank leading to the connecting circuits of the available operators position. As the tripped set of brushes moves up, the brush 114 engages the terminals 118 of the various connecting circuits of the selected position until it encounters a terminal 118 associated with an idle connecting circuit. When this occurs a circuit is completed that extends from battery by way of resistance 126 (see Fig. 4), right-hand back contact and armature of relay 95 resting contact 161 of disconnect key 160, conductor 88, terminal 118 and brush 114 of the cord selector, conductor 99, selector sequence switch contact 305 (5 to 6), winding of relay 30 and selector sequence switch contact 320 (5 to 6) to ground. This operates i'elay 30, which at its right-hand back contact opens the previously-traced energizing circuit of the up-drive magnet 34, thus stopping the cord selector with its selected set of brushes in engagement with the terminals of the idle connecting circuit. At its right-hand front contact relay 30 closes a circuit that applies ground by way of selector sequence switch contact 302 (6) to the winding of the selector sequence switch motor magnet, thus causing the sequence switch to move out of position 6 and come to rest 95 in position 7. When relay 30 operates as a result of finding the idle connecting circuit, it closes a locking circuit for itself by way of its left-hand front Contact and armature, selector sequence switch contact 317 (5 to 6) and resistance 55 to Ybattery which insures the continued energization of relay 30 as long as the sequence switch remains in position 6.

lVhen the selector sequence switch reaches 105 position 7 it closes a circuit that extends from the battery through the motor magnet and contact 410 1) ofthe listening key sequence switch (see Fig. 4), left-hand back contacts and armatures of relays 95 and 110 13, lett-hand back contact and switch spring of relay 81, conductor 87, contact 117 and brush 113 of the cord selector, conductor 98, and contact 307 (7) of the selector sequence switch to ground. As a 115 result the listening" key sequence switch moves from position 1 to position 2, in which position a circuit is closed that extends from battery through the winding of relay 13, listening key sequence switch con- 120 tact 412 (2 to 6) and thence to ground over the path previously traced, including conductors 87 and 98 and selector sequence switch contact 307 (7 Relay 13 in operating closes a locking circuit for itself at 125 its lett-hand front contact and armature, and at its right-hand armature and upper front contact applies a ground extending from spring 154 and its normal contact, sequence switch contact 407 (1 to 4), Contact 130 146, which energizes relay 95,by way of the left-hand winding of that relay, and also causes current to flow serially through the windings of relay 94. Another path to ground is also closed for permitting the flow of current through the left-hand winding of relay 95 and the series windings of relay 94 by way of listening sequence switch contact 413 (2) and the right-hand back contact and armature of relay 81. The windings of relay 94 are so arranged that when current flows through them in series their effect upon .the relay magnet is differential, as a result of which therelay 94 is not at this time energized.

When relay 95 operates as a result of the movement of the listening key sequence switch to position 2, it closes a circuit that extends from battery through selector sequence switch contact 320 (7 to 12), winding of relay 30 (See Fig. 3), selector sequence switch contact 305 (7), conductor 99, brush 114 and contact 118 of the cord selector, conductor 88, resting contact 161 of the disconnect key 160, right-hand armature and front contact of relay 95, left-hand resting contact and switch spring of relay 94, left-hand winding of that relay, and to ground either by way of listening key sequence switch contact 413 (2) and righthand back contact and armature of relay 81, or by way of right-hand front contact and armature of relay 13. The closure of this circuit places the relay'30 in parallel with the right-hand winding and in series with the left-hand winding of the relay 94; but the two relays are so -related to each other in the matter of their resistances and adjustments that the relay 30 is operated as a result of the closure of this circuit, and the relay 94 is not.-

When the relay 30 operates, it closes a locking circuit for itself which extends from battery by way of selector sequence switch contact 320 (7 to l2), winding of relay 30, selector sequence switch contact 309 (1 to 11), left-hand front contact and armature of relay 30, and selector sequence switch contact 310 (7 to 11) to ground. The conductor 99, being connected with the path to ground above traced,.. is itself grounded; and this grounding of the conductor 99, the circuit of which is extended by way of the selector switch and conductor 88 to the differentialV relay 94 of the connecting cord circuit, energizes the right-hand winding and short-circuits the left-hand winding of that relay, thus bringing about its operation. Relay 94 in operating closes a circuit that extends from battery by way of the motor magnet and contact 410 (2) of the listening key sequence switch, and the right-hand armature and switch spring of the relay 94 to ground, the closure of which circuit moves the listening key sequence switch out of position 2. At the same instant relay 30 in operating, as' previously described, has closed a circuit extending from battery through the motor magnet and contact 302 (6 to 7) of the selector sequence switch, and right-hand front contact and armature of relay 30 to ground. Therefore, the selector sequence switch 300 moves out of position 7 at the same moment that the listening key sequence switch 400 moves out of position 2.

Each of the two sequence switches moves at substantially the same speed as the other, and each of them moves through three positions and comes to rest in the fourth position from that where it started. Thus the selector sequence switch moves out of position 7 and comes to rest in position 11, while the listening key sequence switch moves out of position 2 and comes to rest in position 6. As a result, at the same instant that the selector sequence switch is passing through' positions 8, 9-Vand 10 respectively, the listening key sequence switch is passing through positions 3, 4 and 5 respectively. In each of the three positions through which it thus passes,.the listening key sequence switch 400 connects a different one of the three class-of-service register relays R, R and R2, with the fourth conductor 88 of the connecting circuit; and at the same time the selector sequence switch is connecting the extension 99 of conductor 88 with a path which either completes or fails to complete the energizing circuit of the register relay that is at the instant connected with conductor 88. p

The establishment or non-establishment at the selector sequence switch of the energizing path of each of the register relays as it is brought into circuit, is effected through the medium of contact 305 of the selector sequence switch; and the cutting and circuit connection of the contact portion of this cam is the same for all the finder circuits of the group serving a particular group of lines, and is different in each group from what it is in each other group of finder circuits. ln the finder circuit illustrated in Fig. 3, which is assumed to be one of the group of circuits that serves the C or message rate individual lines, contact 305 of the selector sequence switch is so cut and connected that it acts to ground conductor 99 as the selector sequence switch is passingv through position 9. For `the iinder circuits serving group A, this contact is so arranged as to keep conductor 99 open in-all three positions, 8, 9 and 10, through which' the selector sequence switch passes in this stage of the-operation. For the linder circuits serving group B, contact 305 is arranged to apply a ground in position 8,' and to keep the circuitopen in positions-9 and 10. For the finder circuits serving Agroup C, contact I through position 9.

305, as has been stated, is arranged to close the circuit in position 9 and keep it. open in positions 8 and 10. In the case of the nder circuits serving-'the D group of lines, contact 305 is arranged to close the circuit in positions 8 and 10 and keep it open in position 9. In the case of the finder circuits serving the E group of lines, contact 305 is arranged to close the circuit in each of the three positions 8, 9 and 10. In the case of the finder circuits serving the F group of lines, contact 305 is arranged to keep the circuit open in positions 8 and 9 and close it in position 10 of the-selector sequence switch.

In the particular case assumed, where the connection of a calling line in group C is being extended, as the listening key sequence switch moves through position 3 it connects the register relay R, at listening key sequence switch contact 422 (3), with conductor 88 of the connecting circuit. At the same instant the selector sequence switch 300 is moving through position 8; kand as there is no path completed to ground from the eX- tension 99 of conductor 88 in position 8 of the selector sequence switch, the register relay R is not operated. As the listening key sequence switch moves through position 4 it connects the register relay R in circuit at listening key sequence switch contact 422 (4), when selector sequence switch moves Under the conditions assumed, contact 805 of the selector sequence switch applies a ground in position 9; therefore, there is a circuit completed at this instant which extends from battery through the winding of register relay R, listening key sequence switch contact 422 (4), righthand front contact and armature of relay 95, contact 161 of disconnect key 160, conductor 88, contact 118 and brush 114 of the selector sequence switch, conductor 99, and selector sequence switch contact 305 (9) to ground. Consequently register relay R is operated and closes a locking circuit for itself that extends by way of its right-hand front contact and armature and the lower right-hand front contact and armature of relay 18, contact 146 of key 140, sequence switch contact 407 and from thence to ground either at contact 154 of key 150er key 187 depending upon the position of the sequence switch. A moment later the listening key sequence switch moves through position 5 and connects register relay R2 in circuit at listening key sequence switch contact 408 (5). At the same instantthe selector sequence switch is moving through position 10; but as selector sequence switch contact 305, in thecase assumed, does not complete a path from conductor 99 to ground in this position, the register relay R2 remains unenergized. A moment later the listening key sequence switch reaches position 6 and the selector sequence switch reaches position 11, and both switches come to rest.

As a result of the transitory control exercised by the selector sequence switch of the finder circuit over the registering apparatus of the connecting circuit, the register relaysR and R2 remain inert and the register relay R is locked in its operated position. The movement'of the listening key sequence switchl into position 6 brings into operative relation withthe registering relays a group L of lamps which are common to all of the connecting circuits of this particular operators position, and which in the present instance include thesix lamps, AL, BL, CL, DL, EL and FL, The setting that the register'relays havevreceived from the finder circuit is such as to close a circuit for the illumination of lamp CL, this circuit extending from battery through the inner left-hand armature and back contact of relay R2, the inner left-hand armature and front contact of relay R', listening key sequence switch contact 427 (6) and lamp CL to ground. The energizing circuits of the other live lamps are open atk one point or another of the contact points of the three register relays, and consequently lamp CL is illuminated and the other five lamps remain dark. Lamp CL bears or has associated with it a suitable designation that indicates to the operator that the call which has just been extended to her position was originated by a message rate individual line.

t this point it may be well to explain the action that takes place in the case of calls originated by lines of theothergroups having other classes of service. If a line in group A, see Fig. 1, originates a call, it is extended through the medium of a finder circuit of a group, the selector sequence switches of which are adapted not to complete the energizing circuit of any of the register relays R, Rand R2 of the connecting circuit. lVhen the listening key sequence switch reaches position 6 in this case, all three relays are inert, and consequently a circuit is completed that extends from battery by way of inner left-hand armature and back contact of relay R2, inner left-hand armature and back Contact of relay R', inner left-hand armature and back contact of relay R, listening key sequence switch contact 428 (6) and lamp AL to ground. This lamp lights, and the other lamps remain dark, as their circuits remain open at one point or another of the contacts of the three register relays.

Incase one of the lines of group B originates a. call, it is extended Vthrough the medium of a finder circuit of the group in which the selector sequence switch completes a circuit for energizing relay R as the selector sequence switch passes through position 8 and the listening key sequence switch passes through position 3.V The energizingv circuits of the other two relays are not completed in this case, and relaysR and R2 consequently remain inert. Under these circumstances a circuit is completed that extends. from battery through the inner lefthand armature and back contact of relay R2,

the inner left-hand armature and back contact of relay R the inner lett-hand armature and front contact of relay R, listening key sequence switch contact 424 (6), and lamp BL to lights and the other lamps remain dark.

VThe operation where the call is originated by one of the lines of group C has already been described. When the call is originated by one of the lines ot group D, the inder circuit through which the connection is extended completes an energizing circuit for relay R at position 8 of the selector sequence switch, and an energizing circuit :tor relay R2 at position 10 of the selector sequence switch. Consequently a circuit is closed that extends :trom battery through lamp DL, listening key sequence switch contact 426 `(6), outer left-hand back contact and armature of relay R', and outer let-hand'front contact and armature of relay R to ground. Lamp DL therefore lights and the other five lamps remain dark.

When the call is originated by a line of group E, it is extended by means of a nder circuit the selector sequence switch of which completes the energizing circuits of all three relays R, R and R2. In this case a circuit is closed that extends from battery through lamp EL, listening key sequence switch contact 429 (6), outer lett-hand front contact and armature ot relay R2, outer lefthand front contact and armature of relay R and outer left-hand front contact and armature of relay R to ground. This lights lamp EL and leaves the other lamps dark.

Vhen the call is originated by a line of group F, it is extended to an operators connecting circuit through the medium of a inder circuit the selector sequence switch of which closes only the energizing circuit tor relay R2, leaving the other two relays inert.

VIn this case a circuit is completed that extends from battery through the inner letthand armature and front contact of relay R2, listening key sequence switch contact 428 (6) lamp FL, listening key sequence switch contact 425 (6), and outer left-hand back contact and armature of relay R to ground. This lights lamp FL and leaves the other lamps dark. k

The result of the above described circuit arrangement is that the particular lamp that is illuminated upon the extension of a calling line to a connecting circuit ot the operators position, corresponds to the iinder circuit group through which the line is exground. This lamp therefore' tended, and therefore indicates to the foperator the sort of line, with respect to its class of service, that is calling. Conse-V quently the operator'is enable-d to -handle the'connection in the way that the class of service of the calling line requires.

Returning now to the specific case where it is assumed that the call has originated at substation C of line group C, the listening key sequence switch has advanced to posiftion 6, the selectorsequence switch has advanced to position 11, and the lamp CL of indicating group Lv is illuminated. Relay 30 of the finder circuit, which was operated and locked up in position 7 of the selector sequence switch at the time the selector sequence switch and the listening key sequence switch started their synchronous movement, still remains locked up, as its locking eircuit is controlled in contacts of the selector sequence switch that remain closed during this stage of the movement of the switch. Consequently when thev selector sequence switch reaches position 11, a circuit is closed that lextends from battery through the motor magnet and contact 202 (4) of the linder sequence switch,-contact 321 (11)V of the selector sequence switch, left-hand front contact and armature of relay 30, and selector seqilence switch contact 310 (7 to 11) to ground. T e moves from position 4 to osition 5, and in doing so closes a circuit t at extends Jtrom battery through the motor magnet and Contact 304 (11) of the selector sequence switch, finder sequence switch contact 220 (5 to 18), and right-hand back contact and armature of relay 37 to ground. This moves the selector sequence switch Jfrom position 11 to position 12. The movement of the inder sequence switch to positionv 5 and ot the selector sequence switch to position 12 establishes the conversational condition of the finder circuit, in which condition the talking conductors are closed through at inder sequence switch contacts 207 to 5) and 208 (4T)n to 5) and the third conductor of the inder circuit is closed through at contact 209 (435 to 5) of the finder sequence switch. At contacts 306 (11 to 12) and 307 (11 to 12) of the selector sequence switch, the lefthand winding of relay 56 of the finder circuit is included in the circuit of the third conductor.l as are also the winding of relay 13 of the connecting circuit and the windings of the message register 92 of the calling subscribers line. The message register 92 is adjusted so that the amount of current flowing in the circuit at this time is insuticient for its actuation; but the relays 56 ot the finder circuit and 13 of the connecting circuit are both held o 'erated as long as the circuit is closed throng them, 'and serve to hold the connection.

The extending of the connection of the finder sequence switch consequently iso calling linev to the connecting circuit at the Aoperators position actuates a signal for apprising theoperator of the incoming call Yand indicating to her the connecting circuit over which it is being extended. This result is accomplished when the listening key sequence switch moves to position 2, this closing a circuit that extends from battery through the left-hand armature and back contact otrelay 338 (see Fig. 5) lamp 341, conductor 255, and listening key sequence switch contact k418 (2 to 6) and one or the other of the branches extending from listening key sequence switch contact 407 to ground. This lights lamp 341 associated with the connecting circuit over which the call is being extended. A moment later, upon the movement oitl the listening key sequence switch to position 6, as has been described, lamp CL of the class-of-service indicating group L is lighted to inform the operator of the class of service of the calling line. The movement of the listening key sequence switch to position 6 also breaks, at listening key sequence switch contacts 403, 404, 405 and 406, the direct path ot the talking conductors through the connecting circuit and connects them with a loop, including conductors 236, 237, 238 and 239, to which the operators telephone set is connected through the medium of conductors 244 and 245. This loop also includes serially contacts of a ring back key 184, a coin return key 185, and a coin collect key 180.

Through the medium of her telephone set the operator obtains from the calling subscriber the num-ber of the line with which connection is desired, and, alter making the busy test in the ,usual way, completes connection with the called line by inserting the calling plug 334 into the spring jack 339 of that line. `rThe insertion of the plug into the jack completes a circuit that extends from battery through the winding of relay 338, registering sleeve contacts of plug 334 and spring jack 339, and f resistance vto ground. Relay 338 in operating opens the energizingcircuit of lamp 341, and closes, at its right-hand armature and front contact, the energizing circuits for the answering supervisory lamp 335 and the calling supervisory lamp 336. The answering supervisory lamp 335 is prevented from lighting by the shunt closed around it by way of the armature and contact of the answering supervisory relay 331; but the calling supervisory lamp 336 is not at this time shunted, and is consequently illuminated. lhen the called subscriber answers, as a result of the ringing of his bell due to the application of ringing current from generator 199 by means of ringing key 330, the calling supervisory relay-332m operated and shunts and extinguishes vthe calling supervisory lamp 336.

. setting that the register relays R, R and The operator may bring about the disconnection of her tel-ephone set from the connecting` circuit by pressing the common listening-out key 187 or" her position apparatus. This closes a. circuit that extends from battery through the motor magnet and contact 409 (2 to 6) of the listening key sequence switch, conductor 247, and contacts of the operated listening-out key 187 to ground. As a result the listening key sequence switch moves from its listening-in position 6 to its listening-out position 8, 'and in doing so operates its contacts 403, 404, 405 and 406 to disconnect the loop to the operators telephone set and connect thetalking conductors of the cnnnecting circuit straight through. i

At any time during the progress ot' the conversation the operatoris able to listen in on the connection, which she does by pressing the listening-in key 18,3. This Vcloses a circuit that extends from battery through the motor magnet and contact 409 (8) ci' the listening key sequence switch, and contacts of the operated listening-in key 183 to ground. The listening sequence switch consequently moves out of position 8; passes through position 1 as a result of the path to ground closed by way of contact 410 closed contacts of relays 95 and 13, contact 407 (1 to 4) and contact 154 of key 150; passes through position 2 as a result of the path to ground closed Iby way of listening key sequence switch contact 410 (2) and right-hand armature and switch spring' of relay 94; and finally comes to restY in position 6, the listening-in position, in which position the operators telephone set is again connected with the circuit.

At the end of thel conversation the hanging up of their telephone receivers by the calling and called subscribers causes the lighting' of the supervisory lamps 335 and 336. Before taking down the connection the operator may supervise the connection by pressing the listening-in key 183 to bring her telephone set into connection with the circuit, in the manner described above. 1n moving to position 6, the listening-in position, the listening key sequence switch of this connecting circuit again brings the group Lof class-of-seiv-Jice lamps intoy operative relation .ufith the registering mechanisin of the circuit by way of the cains423 to 429 inclusive closed in position 6. The R2 received at the time thecalling` line was extended to the associated connecting circuit has been maintained. for the reason that the locking circuit of any or" the relays that has been operated is held closed by way of the righthand front contact and armature of the holding relay 13 to ground through sequence switch Contact 40T, and tor the reason that the energizing circuit for any of the relays that has not been operated is not again closed as the listening key sequenceswitch moves through positions 3, 4 and 5 in moving to its listening-in position because the selector sequence switch does not at this time operate to close any path to ground from the extension or" the fourth conductor 88 of the connecting circuit. Consequently the registration originally recorded on the relaysQR, R and R2 remains and is again eifective to bring about the lighting oi the particular lamp of the group L that corresponds to this registrationf-in this case, lam CL.

pon supervising at the end of the conversation, the operator is informed by the lighting of the lamp CL that the calling line is a message rate line, and consequently it is necessary for her to make a charge for the completed call in disconnecting, and this she does by pressing' the charge key 150. The pressing of this key closes a circuit that extends from battery through the left-hand winding of relay 81 and contact 154 oi the charge key 150 to ground. Relay 81 in operating disconnects conductor 87 oi the connecting circuit from its normal connection to` battery by way of the winding of relay 13', and connects it instead to battery by way of contact 151 of the key 150, conductor 233 and the windings of relay 295 and position register 297 in series. Relay 295 and position register 297 are thus connected by way of conductor 87 and its extension through the finder circuit with conductor 53 of the calling line and the windings of the message register 92 associated with that line. As a result oi the closure of this circuit relay 295 operates and in doing so short-circuits its high resistance winding. This sufficiently increases the current flow in the circuit to 1 cause the message register 92 of the calling line to operate, and the message register in operating short-circuits its high resistance winding and still further increases the current iiow to a volume suiiicient to operate the position register 297.

Vi hen relay 81 operates as a result of the depression of charge key 150, in opening the normal energizing path through the winding of relay 13 it brings about the release of that relay. Relay 13 in releasing opens the locking circuit of whichever of the registering relays R, R', R2 may have been operated, and thus restores the class-oi-service registering mechanism to normal. lt also closes a circuit that extends from battery through the motor magnet and contact 410 (6) of the listening key sequence switch, right-hand back contact and armature of relay 13, listening key sequence switch contact 407 (4 to 7) and normally closed Contact 182 of key 180 to ground. The listening key Sequence switch consequently moves out of position 6, and cornes to rest in position 8, inasmuch as the energizing path of its motor magnet in position 8, by way of contact 410 (8) and the right-hand back contact and armature of relay 13 and listening key sequence switch contact 407 (7 tol) is now open atcontact 154 of the operated charge key 150.` When the operator releases charge key 150'after registering the call, contact 154 opens the energizing circuit of relay 81 and closes the above-mentioned energizing circuit for moving the listening key sequence switch out of position 8. The deenergization of relay 81 reconnects conductor 87 to contact 412 of the listening key sequence switch, and also to contact 410 oi' the listening key sequence switch by way of the left-hand back contacts of relays 13 and 95 now released. ABut in the position the listening key sequence switch at this moment occupies, the circuit is open at both sequence switch contacts 412 and 410, and consequently current ceases to iiow by way of conductor 87 and its extension ,conductor 98 oi' the finder circuit through the left-hand winding of holding relay 56 of the finder circuit. Consequently relay 56 releases and in doing so breaks at its left-hand armature and switch spring, the circuit to ground that has been maintaining relay 30 of the iinder circuit energized. Relay 30 in releasing Vcloses a circuit for energizing the motor magnet of the selector sequence switch 300 by way or" selector sequence switch contact 304 (12) and the right-hand back contact and armature of relay 30. In moving out of position 12 the selector sequence switch closes a circuit for energizing the motor magnet of the inder'sequence switch 200 by wa of finder sequence switch Contact 202 (5) and selectorsequence switch contact 310 (13 to 17). ris a result the iinder sequence switch moves out of position 5 and comes to rest in position 18, and the selector sequence switchafter moving out of position 12 also comes to rest in position 18. When the selector sequence switch reaches position 18 it closes a circuit that extends from battery throughthe down-drive magnet 35 of the cord selector CS, conductor 90, and selector sequence switch Contact 311 (18) to ground. The cord selector is thus returned to its normal position, and upon reaching normal closes a circuit that extends from battery through the motor magnet and con tact 303 (18) ci' the selector sequence switch, conductor 31, and segment Y and associated brush of the cord selector commutator to ground. The closure of this circuit moves the selector sequence switch out of position 18 and returns it to its normal or 1 position. In the meanwhile the movement of Jthe nder sequencevswitch to position 18 has 'completed a circuit that extends from batthe line finder.

tery through the down-drive magnet 62 of the line inder LF, conductor v60, andV selector sequence switch contact 218 V(18) to groundl Upon the return of the linefinder tonormal as a result ofthe closure of this circuit, a circuit is closed that extends from Vbattery throughthe motor magnet and contact 203 (18) of the finder sequence switch, conductor 69, and segment Y and corresponding brush of `the line findercommutator to ground. This returns the finder :sequence switohr200 to its normal or 1 v position, from/which itis afterward moved, by the closure of a-circuitthrough contact [204 (1)'in any desired or convenient way, when the associated' Vfinder circuit 'is lagain l f next in order to respond to acalling line.V

From the above it'may be seen that by the act of depressing/.and releasing the charge key 150, the operator not only registers the call on the message re ister of thecalling line, but also brings aout the restoration to normal of the listening key sequence switch, the selector sequence switch, "the Vfinder sequence switch, the cordselector and The operator, of course, also withdraws the calling plug 334 from the calling line spring jack l339l as part of the operation of taking down the connection.

If itl be assumed that the extension of the calling line to the operators connecting circuit, and the supervising of the connection before taking it down is accompanied by the lighting of lamp ALof the signal group L, thus indicating that the calling line risv a'flat rate line of line .group A, then the operator Yhas no occasion to press the charge key 150, and accomplishesthe disconnection by pressing the disconnect-key 160. This closes a circuit that extends .from battery through the right-hand winding of relay 81 and contact 163 of vdisconnect'key 160 to ground. Relay 81 in operating breaks, at its lefthand switch springV and vresting contact, the holding circuit which is vincluded the winding ofthe holding relay 13 of the connecting circuit. Relay 13 in releasing establishes at its right-hand back -contact an energizing circuitV for the motor magnet of listening key sequence switch 400 by way of sequence switch contact 410 (2, 6 and 8), and listening key sequence switch cam 407 to ground over one or the other of the ground paths controlled by cam 407. As a-result listening key sequence switch 400 moves from position 8 and returns to its normal or 1 position. The operation of relay 81, as a resultV of pressing the disconnect key 160, does not complete any alternative energizin vpath to battery for the third conductor 8 and its included apparatus,` as the charge Ykey 150 is resting in its normal position and Vconsequently is not acting to connect conducltor 87 with the position register apparatus.

ter, the

vand an operators position, of finder circuits `for extending said Therefore the holding relay 56 of the finder circuit is released, and in releasing brings about the restoration of the finder circuit switches as hereinbefore described.

If the extension of ka calling line to the operators connecting circuit andthe supervision of the circuit before disconnection is accomplished by the lightingof lamp FL of the lampgroup L, thus indicating to the operatorthat the `callinfr line is a pay station linefofline group FP, then, vbefore disconnecting, if the connection with the called line has been successfully established, the operator presses the charge key 150. This has the effect of applying current from the positive pole of a source of high potential current 266 by way of conductor 232 and contact 152 of charge key 150 to tip conductor 85 of the connecting circuit and thence over the corresponding conductor of the finder circuit tothe magnet of the pay station coin box at the subscribers station. This lcauses the operation of the magnet to rcollect the deposited coin. The arrangement of pay station coin box circuits is Well known inthe art, and need not be specifically dcscribed. At the same time the charge key acts to bringv the position-register apparatus into lconnection with the circuit, in a manner previously described Vline is not provided witha message regisposition registering apparatus does not function. Upon the release of the chargekey 150, the disconnection and rcstoration of the circuits and apparatus to normal takes place inthe manner hereinbefore described. If the connection from the calling pay station line has not been successfully completed, the operator, while listening in on the connection, presses the coin return key 185 of her position apparatus. AThis has the effect of applying current from the negative pole of the high potential source 266 to the tip yside of the calling pay station line to `operate the coin box magnet to bring about the return'of the deposited Acoin in a well-known manner.

In like manner, when the extension of a -call to one of the operators connecting circuits is accompanied by the lighting of lamp BL, DL yor EL, the operator knows that -thevcalling line is a flat rate party line, a message rate party line, or a message rate PBX line, as the case may be, and thus is directed as to the routine to be followed and the operations to be performed in handling each connection.

What is claimed is:

-1. The combination with telephone lines groups of telephone lines to said position, distinctive controlling means associated with each group oi' finder circuits, and indicating mechanism at said but as the pay station -f operators position selectively responsiveto said distinctive controlling means of the various oroups of finder circuits.

2. r.liihe combination vvithv an operators position, of a plurality of groups of trunk lines for extending connections to said operators position, indicating mechanism at said operators position, and means associated with each group oftrunlrlines and dierent for the dierent groups for causing the selective operation of said indicating mechanism to indicate the group of trunk lines employed in extending a connection to` said operators position.

3. The combination with an operators position, of a plurality of trunk circuits for extending connections thereto, selective indicating mechanism at said operators position, and means associated With each of said trunk circuits and automatically actuated in the extension of a connection by said trunk circuitfor causing an indication of said indicating mechanism diiierent from the indication caused by the extension of a connection by another of said trunk circuits.l

4. The combination with telephone lines and an operators position, of groups of `finder circuits for extending said telephone lines to said position, distinctive controlling means associated with each group of finder circuits, registering mechanism at said operators position selectively responsive to said controlling means and arranged to be brought into transitory connection with said controlling means in the extension of a telephone line to said position, an electrical responsive ,device adapted to be selectively controlled by said registering mechanism,

Vand means for bringing said responsive device temporarily into' operative relation With said registering mechanism. v

5. The combination with telephone lines and an operators position, of `groups of iinder circuits for extending said telephone lines to said position, distinctive controlling ymeans associated vvith each group of finder circuits, registering mechanism at said operators position selectively responsive to said controlling means of the various groups, and a signal device at said operators position adapted to be brought temporarily into operative relation with said registering mechanism and to be selectively operated in accordance With the selective response oi said registering mechanism.

`.6. The combination With an operators position provided With a plurality of connecting circuits, of a plurality of groups of trunk lines for extending connections'thereto, registering mechanism for each of said connecting circuits, distinctive controlling mechanism associated With each group of trunk lines for effecting a correspondingly distinctive setting of the registering mechanism of the connecting circuit to which a trunk line is extended, a si nal device adapted tobe selectively contro led by said registering mechanism in accordance` with the setting of said mechanism, and means for bringing said signal device into voperative relation with the registering mechanism of any of said connecting circuits.

7 The combination with an operators position provided With a plurality of connecting circuits, of a plurality of circuit-extending means for extending Vconnections to said connecting circuits, registering mechanism for each connecting circuit, means for eftecting a characteristic setting of the registering mechanism of a connecting circuit in extending a `connection to said connecting circuit, said setting varying in accordance With the particular circuit extending means employed, and means common to the connecting circuits of said operators position, and

adapted to be brought into temporary association with any of them, lfor giving a signal indication in accordance with the setting of the associated registering mechanism.'

8. The combination With an operators position provided with a plurality oi' connecting circuits, oi' a plurality of. telephone lines adapted forV differenti classes of service, means `for extending said lines to said connecting circuits, registering mechanism for each connecting circuit responsive to the extension of a line to said circuit and adapted to take a characteristic setting in accordance With the class of service of the extended line, and a responsive device adapted to be brought into koperative relation with the registering mechanismof any of .said connecting circuitsand to be selectively operated in accordance with the setting of the registering mechanism with Which it is at the-time connected.

v9. The combination 4With tWo `groups of telephone lines, the linesof each group being adapted or a different class of service,

lines, an operators position, connecting circuits at said position, registering mechanism associated withl each connecting circuit,

means for extending said finder circuits to said connecting circuits, a signal device com- .mon to the circuits oi.' said position, means for bringingsaid signal device into operative relation with the registering mechanism of any connecting circuit to which a inder circuit is extended, and distinctive means associated with the finder circuits of each group for selectively controlling said registering mechanism to cause a distinctive indication of said signal device.

11.` The combination with two telephone lines adapted tor different classes oi? service, of an operators position, connecting circuits at said position, registering mechanism associated'with each connecting'circuit, two finder circuits, one of whichis adapted to extend one of said telephone lines and the other oi which is adapted to extend the other ot said telephone lines to a connecting circuit at said operators position, a signal device common to the circuits of said position, means for bringing said signal device into operative relation with the registering mechanism of any connecting circuit to which a line has been extended, and means associated with each `finder circuit for selectively controlling said registering mechanism to cause distinctive indication of said signal device to indicate the class of service of the extended line.

12, The combination with a plurality of telephone lines divided into groups in accordance with the class of service of the various lines, an operators position, a different group @t trunk lines serving each of said groups ot' telephone lines, each group of trunk lines being adapted to extend calling lines of the corresponding group to said operators position, distinctive controlling mechanism associated with each group of trunk lines, and, indicating mechanism at said operators position selectively controlled by said distinctive controlling mechanism for indicating the trunk line group through which a call is extended to said operatorie position.

13. The combination with a connecting circuit, of a plurality ot' trunk circuits, means for extending the same to said connecting circuit, responsive devices associated with said connecting circuit, a switch for bringing said responsive devices successively into operative relation with said connecting circuit, a switch associated with each trunk circuit, controlling paths brought by the last mentioned switch into successive connection with an extended trunk circuit at the same instant that the first mentioned switch brings the corresponding responsive devices into operative relation with the connecting circuit, and signals selectivelyV operated under the joint control of said responsive devices.

14. The combination with a connecting circuit, of a plurality of trunk circuits for extending connections thereto, a plurality of responsive devices, a switch associated with said connecting circuit for bringing said responsive devices successively into operative relation with said connecting circuit, means associated with each of said trunk circuits for controlling the Venergization of said responsive devices as the same are successively brought into operative relation with the connecting circuit to which the trunk is extendech'said means differing for the different trunk circuits and controlling the energization of said responsive devices in different combinations in accordance with the particular trunk that is extended to said connecting circuit, and signals jointly controlled by said responsive devices and selectively actuated in accordance with the operation or non-operation of various ot said responsive devices.

15. The combination with a connecting circuit, of a plurality of trunks adapted for extension thereto, a controlling switch associated with each trunk circuit, a switch associated with said connecting circuit and operated synchronously with the controlling switch of the Vextended trunk, controlling paths associated with the controlling switches ot said trunks and differing for the different trunks, indicating mechanism, and energizing paths therefor each controlled by a different one of said controlling paths in the synchronous operation of said switches, whereby said indicating mechanism is caused to give different signal indications in accordance with the particular trunk that is extended to said connecting circuit.

16. The combination with a connecting circuit, ot a plurality of trunks, means tor extending any of said trunks to said connecting circuit, controlling paths differing 4in their nature for each trunk, responsive devices, switches adapted for synchronous operation associated with said trunks and said connecting circuit, means for actuating said switches of said connectingcircuit and of an extended trunk upon the extension of the trunk to bring said controlling paths successively into operative relation with said trunk as the corresponding responsive devices are successively brought into operative relation with said connecting circuit, and a signal device jointly controlled by said responsive devices, and selectively operated in accordance with the particular trunk that is extended to said connecting circuit.

17. The combination with an operators position havinga plurality of connecting circuits, of means for extending connections to said connecting circuits, a plurality of relays at said operators position, a switch automatically operated in the extension of a connection to one of said connecting circuits or bringing said relaysrsuccessively into operative relation with the connecting circuit to which the connection is extended,

means associatedl with said connection-extending means for closing or failing to close an energizing circuit for each of said relays as it is brought into operative relation with the connecting circuit, and a signal device under thejoint control of said relays and selectively actuated in accordance with the operated or non-operated condition of each of said relays.

18. The combination With an operators position having a plurality of connecting circuits, of a registering mechanism for each connecting circuit provided with a plurality of relays, means for controlling said relays to effect a larger number of circuit permutations than there are relays in the registering mechanism, a signal device common to ysaid position having a plurality of indicators each adapted to respond to a different circuit permutation of said registering mechanism, and means for bringing position having a plurality of connecting Y circuits, of a signal device common to said position having a certain number of indicators, a registering mechanism for each connecting circuit having a lesser number of relays, means for extending connections to any of said connecting circuits, means associated With said connection-extending means for controlling said relays to effect as many circuit permutations as there are indicators in said signal device, each indicator being adapted to respond to one of said circuit permutations, and means for bringing said signal device into operative relation with any of said registering mechanisms.

In Witness whereof, I hereunto subscribe my name this 12th day of May, A. D., 1919.

SAMUEL B. VILLIAMS, Jn. 

